Objectives and programs to be pursued in the Cerebrovascular Clinical Research Center at the University of Maryland during the next year represent a continuation and logical extension of projects and work accomplished during the previous year of support. These include ultrastructural studies of intracranial blood vessels and their innervation, and of alterations in vascular endothelium in ischemia and atherogenesis. Studies of microcirculatory changes, simultaneous ultrastructural abnormalities in the neural parenchyma and of capillary permeability changes in areas of regional cerebral ischemia are also in progress and will continue. Another project involves definition of risk in a hypertensive urban black population, utilizing screening techniques developed during previous years of this program. Studies have been carried out on vascular pathology and changes in blood brain barrier resulting from intracranial hypertension. Other studies involve the biophysics, reactivity and pharmacological responses of cerebral blood vessels in experimental animals. A project is in progress to evaluate receptor activity in plegic-paretic limbs of patients with acute stroke. Another project is attempting to develop a photofluorimetric method of studying the retinal circulation in patients with carotid arterial disease. An investigation is underway to further delineate the influence of nutritional vs. hormonal factors in genesis of vascular fatty streaks during puberty in pigs. BIBLIOGRAPHY REFERENCES: Nelson, E., Sunaga, T., Shimamoto, T., Kawamura, J., Rennels, M.L., and Hebel, R.: Ischemic Carotid Endothelium: Scanning Electron Microscopic Studies. Arch. Pathol. 99: 125, 1975. Gertz, S.D., Rennels, M.L., and Nelson, E.: Endothelial Cell Ischemic Injury: Protective Effect of Heparin or Aspirin Assessed by Scanning Electron Microscopy. Stroke 6:July-Aug., 1975.